(A) provides some evidence that the craters could be volcanic, but doesn't help to rule out meteorites as an alternate cause.(C) and (D) both weaken the argument that the craters are volcanic.(E) is irrelevant. It makes it unlikely that the craters were all caused by meteorites *from the same shower*, but the craters in question are all different ages, so no one's claiming that they were all caused by a single meteor shower in the first place.

(B) is relevant, since it tells that it's unlikely that eight meteorite craters would form a straight line, even if the meteorites hit at different times. This leaves volcanic activity as the only likely cause for the craters, which strengthens the argument.

(E) is a particularly good bit of "LSAT trickery" - it's an attractive answer because it does a great job of ruling out a possible alternate explanation, until you realize that the alternate explanation it's ruling out isn't the one that the passage was proposing.